Azacyclohexane compounds and methods for preparing them



AZACYCLOHEXANE COMPOUNDS AND METHODS FOR PREPARING THEM William F. Bruce, Havertown, and Julius Diamond and Richard De Vere Huber, Philadelphia, Pa., assignors to American Home Products Corporation, New York, N. Y., a corporation of Delaware No Drawing. Application September 3, 1954, Serial No. 454,196

9 Claims. (Cl. 260294.3)

This invention relates to azacyclohexane compounds and more particularly to bis-quaternary salts comprising said heterocyclic rings.

The compounds of the invention fall within the following general formula:

R4 CED-CH:

ots ofizoa wherein R3 stands for hydrogen or a lower alkyl, while R4 represents either hydrogen, --COO-lower alkyl, or OCO-lower alkyl.

The compounds of the invention are pharmacologically useful in the veterniary or human field in that they have been found to possess curare-like, muscle-relaxing action among other pharmacological actions. Compounds showing the strongest curare-like action are those where R3 stands for hydrogen with R4 representing an ester of the COO-lower alkyl type, and with the alkylene chain having 7 to 8 carbon atoms.

The compounds may be prepared by heating the azacyclohexane with an akylene dihalide preferably using a molar ratio of at least 2:1 azacycloalkane to halide.

It has been found that substantial yields may be achieved if the reaction takes place in a solvent and if the solvent medium is highly polar, having a high dielectric constant or dipole moment under standard conditions (20 C.) of about 2.5 Debye units or greater. The dielectric constant should be about 10 (epsilon) or greater and preferably from about to 40 when measured under standard conditions. Additionally the highly polar solvent should have a boiling point above about 70 C. since the reaction goes best and with the greatest yield within the range of about 70 to 100 C. although the reaction will take place within the range of about 25 to 120 C. Examples of preferred solvents are the nitro and nitrile compounds such as nitrobenzene, nitromethane, nitroethane, l-nitropropane, acetonitrile and benzonitrile.

ICC

If the precipitate that forms from the aforesaid reaction is large, the reaction mixture is chilled with icewater and then treated with a large volume of relatively low boiling ketone, such as acetone or methyl-ethylketone. If little or no precipitate forms, the reaction mixture is treated with a relatively non-polar solvent such as diethylether, heptane or benzene. Surprisingly, an excellent granular product is obtained by adding the reaction mixture gradually to the non-polar solvent, rather than using the reverse procedure.

The desired product obtained as a precipitate is separated from the reaction mixture, washed with non-polar solvent and dried. If further precipitation is sought, the product may be recrystallized from a mixture of a low boiling alcohol of 1 to 5 carbon atoms and low. boiling ketone having 3 to 6 carbon atoms, ether, or hydrocarbon solvent being used additionally if the crystallization takes place too slowly.

The following examples disclose the invention in specific form. It should be made clear that the following examples are merely for illustrative purposes and are not to be considered limitative of the invention.

EXAMPLE- 1 1,4-bis-(I-methyl-4-phenyl-azacyclohexane-onium')- tetramethylene. dibromide N-methyl-4-phenyl-azacyclohexane, 3.5 g. (0.020 mole), 1,4-dibromobutane, 1.9 g. (0.0090 mole), and nitrobenzene, 15 ml., were heated at 100 C. for 21 hours.-After cooling to room temperature, the mass was stirred with acetone, 200 ml., and filtered. The solid was. dissolved in a mixture of acetone and methanol (minimum) and reprecipitated by the addition of a large volume of ether.

After filtering and air-drying, the product was obtained,

melting at 212-15 C.

Analysis.--C2sH42N2Br2:

Nitrogen Bromine Percent Percent Oalcd 4. 28. 3 Found 4. 68 28. 3

EXAMPLE 2 1,5-bis- (1-methyl-4-phenyl-azacyclohexane-onium) pentamethylene dibromide Nitrogen Bromine Percent Percent Oalcd 4. 83 27. 6 Found 4. 61 27. 5'

EXAMPLE 3 1,4-bis- (4-carbethoxy-1-methyl-4-phenyl-azacyclohexaneom'um) -tetramethylene dibromide 4 carbethoxy 1 methyl 4 phenyl piperidin'e, 2.5 g. (0.010 mole), 1,4-dibromobutane, 0.86- g. (0.0040 mole) and nitrobenzene, 5 ml., were mixed and heated at C. for 20 hours. The cooled, crystalline mass was stirred well with acetone, filtered and the ppt. stored under dry ether for 3 days. This gave the product, melting at 216-218 C.

Analysis.CstHoN2O4Br2: Nitrogen-Calcd., 3.94%. Found, 3.68%

EXAMPLE 4 1 ,5 -bis-(4-carbethoxy-N -methyl-4-pheny l-razacycl ohexaneonium) -pentamethylene-di bromide The compound 4-carbethoxy-1-methyl-4-phenyl-piperidine, 2.5 g. (0.010 mole), 1,5-dibromopentane, 0.92 g. (0.0040 mole), and nitrobenzene, 5 ml. were mixed and heated at 100 C. for 20 hours. The resulting cooled solution was treated with a large volume of ether, and the precipitate that resulted was reprecipitated' by dissolving. in acetone and adding: a large volume of ether. After washing well with ether for 3 days, the desired product was obtained and began to-melt at 90" C.

A nalysii-CasHszNzOtBrz:

Nitrogen Bromine Percent Percent Galorl' 3. 86 2231 Found 4; 08 22. 0

EXAMPLE 5 1 ,6 -bis- (4 -carbethoxy-1 -methyl-4 phenybazacyclohizxan eonium) -hexamethylene dibromide 4-carbethoxy-l-methyl-4 phenyl azacyclohexane, 216 g. (0.0105 mole), 1,6-dibromohexane, 1.1 g. (0.0045 mole), and nitrobenzene, 5.0 ml., were mixed and heated at 100 C. for 2 hours. After cooling down to room temperature, the crystalline mass was treated with acetone, 50 ml., cooled in ice-bath, and filtered. The solid was washed with acetone and ether, and finally stored overnight under ether. This gave the product, melting at 225227 C. with decomposition.

Analysia-CaeHseNaOrBrz:

Nitrogen Bromine Percent Percent Oalcd 3. 79 21. 7 Found..- 3. 79 21. 1

EXAMPLE 6 1,7-bis- (4-carbeth'oxy-I-methyl-4-phenyl azacyclohexaneonium) -heptamethy lene! d i brom ide Nitrogen Bromine Percent Percent (1111M 3. 72 21. 3 Fnnnrl 3. 80 21. 1

EXAMPLE 7 1,8-bis-(4-carbetkoxy-1-methyl-4ephenyl-azacyclohexaneoniumJ-octamethylene dibromide 4 carhethoxy- 1 methyl':- 4 phenylpiperidine, 2.5

g. (0.010 mole), 1,8-dibromooctane, 1.3 g. (0.0050 mole), and nitrohenzene, 4.0 ml., were mixed and heated at C. for 18 hours. After cooling the solution in ice, it was diluted with 30 ml. of acetone, and after 24 hours, the crystallization was enhanced by stirring and treating dropwise with 150 ml. of dry ether. The solid was washed and dried well under ether. This gave the product, which melted at ZOO-204 C.

Analysis.-CasH5sN2OiBrz: Nitrogen--Calcd., 3.65%. Found, 3.67%.

EXAMPLE 8 1,1 O-bis- (4-.carbeth0xy-1-methyl-4-pkenyl-azaeycl0hexaneom'um) -decamethylene diiodide 4 carbethoxy 1 methyl 4 phenyl piperidine, 2.6 g. (0.0105 mole), 1,10-diiododecane, 2.0 g. (0.0050 mole), and nitrobenzene, 5 mL, were heated at 100 C. for 15 hours. The solution that resulted was cooled to room temperature, diluted with acetone, heated with charcoal, and filtered. On further dilution with acetone and cooling to 5 C. the product crystallized. More crystals were obtained by cooling with a Dry-Ice and acetone bath and adding dry ether gradually. The solid was filtered, washed with 1:1 acetonezether and finally washed and dried under ether. This gave the product, melting at 19820l C.

Nitrogen Iodine Percent Percent Cnlnd 3. 15 28. 5 Fmmrl 3. 75 28. 2

EXAMPLE 9 1 ,6 -bis-( 1 ,3-dimethyl-4-phenyl-4- propi onoxy-azacycloh exane-om'um) '-hexamethylene dibromide Nitrogen Bromine Percent Percent Galcd 3. 66 20. 9 Fmmd' 3. 68 21. 2

We claim:

1. The process comprising reacting an azacyclohexane with an alkylene dihalide having from 4 to 12 carbon atoms in the presence of a highly polar organic solvent at a temperature in the range of about 25 to about C.

2. The process comprising reacting an azacyclohexane with an alkylene dihalide having from 4 to 12 carbon atoms at a temperature in the range of about 70 to about 100 C. in the presence of a highly polar solvent having a boiling point above ahout70 C. and then commingling said reaction mixture with a non-polar solvent.

3. The process of claim 2'; wherein the reaction mixture is gradually added to said non-polar solvent.

4. A quaternary ammonium salt which contains the cation CH: H5

wherein R3 represents a member of the group consisting 10 5. A quaternary ammonium salt containing the cation 15 6 wherein alk stands for an alkylene radical of 4 to 10 carbon atoms.

6. The compound, 1,4 bis-(4-carbethoxy-1-methyl-4- phenyl-azacyclohexane-onium) tetra methylene dibromide.

7. The compound, 1,S-bis-(4-carbethoxy-1-methyl-4- phenyl azacyclohexane onium) pentamethylene dibromide.

8. The compound, 1,6-bis-(4-carbethoxy-l-methyl-4- phenyl azacyclohexaue onium) hexamethylene dibromide.

9. The compound, 1,8-bis-(4-carbethoxy-l-methyl-4- phenyl azacyclohexane-onium) octa methylene dibromide.

References Cited in the file of this patent Collier: Nature, volume 164, pp. 491-492, 1949. Libman et a1.: Journal of the Chemical Society of London for 1952, pp. 2305-2307.

Taylor: Journal of the Chemical Society of London for 1951, pp. 1150-1157. 

4. A QUATERNARY AMMONIUM SALT WHICH CONTAINS THE CATION 